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Microstrip Line Calculator
Calculate microstrip characteristic impedance, effective dielectric constant, propagation velocity, delay, wavelength, and electrical length from PCB trace geometry and substrate material.
Input Parameters
Results
Use this as a first-pass controlled-impedance estimate; confirm final dimensions with the PCB stackup provider.
Equations Used
Width-to-Height Ratio:
u = W / H
Characteristic Impedance:
Uses common quasi-static microstrip impedance approximations with an effective-width correction for copper thickness.
Propagation Velocity:
v = c / sqrt(εeff)
Propagation Delay:
Delay = Length / v
Electrical Length:
Electrical length = 360 deg × frequency × delay
Frequently Asked Questions (FAQ)
Q1: What does this microstrip line calculator do?
It estimates impedance, effective dielectric constant, delay, guided wavelength, and electrical length from PCB stackup and trace geometry.
Q2: What is microstrip characteristic impedance?
It is the transmission line impedance of a PCB trace over a reference ground plane. RF layouts often target 50 ohms.
Q3: Why does substrate height matter?
A larger height to the ground plane generally raises impedance, while a wider trace generally lowers it.
Q4: Does copper thickness affect impedance?
Yes. Copper thickness changes the effective conductor width and can shift controlled impedance slightly.
Q5: Is this accurate enough for manufacturing?
It is suitable for early design estimates. Final impedance should be checked with the PCB manufacturer stackup or a field solver.
Q6: Can this be used for RF PCB design?
Yes, for first-pass RF feed line and high-speed routing estimates.
